Two new studies, released Monday in the American Medical Association’s journal of internal medicine, provide new evidence suggesting legalization of medical and recreational marijuana reduced opioid prescription rates, an important development as America continues to face a crisis of opioid overdose deaths.

The two studies use data from the Medicaid and Medicare Part D programs to analyze the impact that marijuana legalization has had on opioid prescription. Currently, 30 states and the District of Columbia have laws that permit the prescribing of marijuana for medical purposes in some form or another. A further eight states permit recreational use of marijuana, with California beginning weed sales in January of this year.

Medicaid, which covers low-income and disabled Americans, saw a significant drop in opioid prescriptions in those states that had implemented medical and recreational marijuana laws. Examining the period between 2011 and 2016, during which time Medicaid was expanded under Obamacare, authors Jason Hockenberry and Hefei Wen found that medical marijuana laws were associated with an average reduction in the opioid prescription rate of 5.88 percent. States with recreational marijuana laws saw an average reduction of 6.38 percent.

That adds up to a substantial decrease in the rate of opioid prescription. Hockenberry and Wen estimate medical marijuana cuts opioid prescription rates by 39.41 prescriptions per 1,000 Medicaid states enrollees, and recreational marijuana cuts prescription rates by a similar rate. For context, there were about 665 opioid prescriptions per 1,000 people in the U.S. in 2016.

Read more